The adsorption of As(V), Pb(II), Cd(II), and Cr(III) ions from aqueous solutions on natural and modified chabazite was studied. The functionalization of chabazite was performed via a protonation and calcination with the aim of generating Lewis acid sites to improve its anion exchange properties. The surface and physicochemical properties of both adsorbents were studied and compared. The adsorption isotherms of tested heavy metal ions were quantified and modeled to identify the best isotherm equation. Steric parameters for the adsorption of these ions were also calculated with a monolayer statistical physics model. Natural chabazite showed the maximum adsorption capacity for Pb(II), while the modified zeolite improved its As(V) properties in 79%. These results showed that the modified zeolite was able to remove both cations and anions from aqueous solution. The application of this functionalized chabazite can be extended for the removal of other anionic pollutants from water, thus opening the possibility of preparing new adsorbents with tailored properties for water treatment.

Dental restoration materials are susceptible to bacterial biofilm formation, which damages the restorations and causes oral health problems. Therefore, to overcome this, silver nanoparticles (AgNPs) are studied widely due to their antimicrobial, anti-inflammatory and healing properties. The purpose of this study was to develop a strategy for incorporating AgNPs onto the surface of bisacrylic resin (Bis) to evaluate its antibiofilm effects using Streptococcus sanguinis and Actinomyces naeslundii . AgNPs with an average size of 25 nm at two different concentrations were dispersed on the Bis surface (Bis-AgNPs) by mechanical deposition. Ag release was quantified until 7 days of incubation. Bacterial growth was assessed using a viability assay kit and observed using confocal microscopy. The biofilm biomass was quantified using arbitrary fluorescence units. Cell viability was evaluated using an MTT assay. The results showed that Bis-AgNPs significantly inhibited biofilm formation along with a significant difference in the viability of human gingival fibroblasts. The quantification confirmed a decrease in Ag release over time, and elemental mapping showed AgNP penetration up to 10 µm from the surface. Therefore, it was concluded that Bis-AgNPs presented enhanced antibiofilm properties, even at a concentration with no adverse effects. Therefore, this nanocomposite may be a promising alternative for biofilm control in temporary restorative materials.

The San Luis Potosí valley is an endorheic basin that contains three aquifers: a shallow unconfined aquifer of alluvial material and two deep aquifers, free and confined. The groundwater contamination documented for the shallow aquifer generates contamination of the deep unconfined type aquifer, from which part of the population’s drinking water needs are met. This study records incipient anthropogenic contamination of two types: biogenic and potentially toxic trace elements. The studied contaminants include fecal coliform bacteria, total coliform, nitrate, and potentially toxic elements such as: manganese ($Mn$), mercury ($Hg$), arsenic ($As$), and cadmium ($Cd$). This contamination in some locations exceeds the permissible limit for human consumption. Some major consequences to health, including severe illness, may be caused by the trace elements. The present results give a first signal about the contamination of the deep unconfined type aquifer due to anthropogenic activity in the valley. This is a priority issue because this aquifer supplies drinking water, and in the short or medium term it will have an effect on public health.